Process of coating knit articles and products thereof



Nov. 21, I939. I VL.'G.,COPEMAN INVENTOR ATTORNEYS Reisoued Noy.2 1,1939

PROCESS OF COATING KNIT ARTICLES AND PRODUCTS THEREOF Lloyd Grofl'Copeman, Lapecr, Mich., assignor to Copeman Laboratories -Company,Flint, Mich, a corporation of Michigan Original No. 2,172,251, datedSeptember 5, 1939,

Serial No. 127,714, February 25, 1937. Application for reissue September9, 1939, Serial No.

' 16 Claims.

1 This invention relates'to a process of coating knit articles andproducts thereof, and has to do particularly with a novel process ofcoating or treating knit articles formed of thin fine threads 6 whichare easily subject to "ladderin g or runs" such, for instance as sheersllk stockings.

This application is a continuation in part of my application Serial No.708,163 filed Jan. 24,'

1934, which is a continuation in part of another 10 application SerialNo. 407,363, filed November Heretofore, the tendency of thin fine knitarticles to .ladder has been considered more or 1 less a necessarydisadvantage, and in general this tendency to ladder" or "run has beenpresent in fine, thin, knit articles, such as stockings, regardless ofthe quality thereof. Attempts have been made to treat knit articles toreduce the tendency to run" or "ladder", some of which attempts haveembodied the stiffening of the threads so as to make it difficult forone loop to slide-past the other, while other attempts have embodied thetreating of knitted articles formed of artificial cellulose threads witha-gas or a solution so as to attach the artificial fibers and melt orstick them slightly together.

It is the object of the present invention to treat a knitted articlewith a coating material in such a manner that the various threadsforming the loops will be covered with a binding material at the pointsof contact. This coating may ,be of any desired substance but I preferto use what is known as rubber latex. This latex may be applied in manydifferent ways such as by dipping or spraying but the point is that itis applied in its original fluid state, then substantiallyremoved fromthe knit article so as to leave the spaces between the threads open anda very thin' coating around the threads and/or around the 40 pointswhere the loops contact, the thin coating is then allowed to coagulatewhereby to form a thin elastic and flexible sheath to prevent anypossiblity of ladderin'g or running" in the final product; the sheatharound each discrete thread Fig. 2 is an enlarged view similar to Fig. 1but illustrating the manner of isolating the coating to the points ofcontact between the loops.

Fig. 3 is a, view similar to Fig. 1, but showing v the different type ofweave, the thickness of the sheath of rubber being considerablyexaggerated in the third step, the actual opening between the threads inthe third step being substantially the same as that shown in the firststep.

Fig. 4 is a sectional view taken on line H of Fig. 3.

The present process is applicable to knit articles formed of any kind ofthread and in any form of web, but it will be recognized that it has no,particular function unless such threads are the entire article iscovered with a thin layer of latex such as shown at 3 in Fig. 1. Thisthin film of latex covering all of the loops is then preferablysubjected to a blast of air so that substantially all of the thin filmof latex is blown away leaving a very ,thin coating ofthe latex aroundeach thread as at 4 and preferably around each point 5 where the threadsor loops contact.

Itis the surrounding of the knots or points of contact 5, by the rubberlatex, that solves the problem. After substantially all the film oflatex has been blown away or otherwise removed, the article may then bevulcanized by any of the well known processes. This vulcanizing, steptakes but a relatively short time after which the stocking 'or otherarticle is in condition for com-- mercial use.

The latex used in coating the knitted article, may, of course, be tintedso as to produce any color desired. In all instances, I prefer to use asthin a solution of latex as possible and to produce a final articlewherein the individual threads \are also coated with as thin a film oflatex as possible. In those instances where all the threads and theentire length of each thread is coated,

.it will be obvious that such latex coating must either be transparentor else be tinted to obtain the desired shade; It may be desirable toknit the article with the original undyed or uncolored thread and obtainthe desired color, by the coatmg- I It will be understood that thissolution of latex may be applied to the stocking or other article inmany different ways, and the present invention is not concerned with themanner of applytex I may subject the article to such a blast ofpressure, or so initially apply the latex that it covers only suchportions of the threads as contact in forming the loops so as to formwhat might be termed knots of rubber latex at all-the points of contact.Such knots may be designated Ii as shown in Fig. 2.

It will be understood that I am in no .waylimited to the particularcoating utilized in covering the threads or the joint between thethreads. the gist of the invention being in the permanent joining of theloops at their points of contact by coating the loops so as to form whatmight be termed "minute knots. In the case of isolating-the coating tothe points of conprocess may be carried out, sheer silk stockings,

either betore or after being dyed, are preferably washed in an alkalinesolution to clean the flbers.

.After this the stockings may be rinsed in clear water and then machinedried by a centrifugal action. An intermediate step may be introducedhere, namely, that or wetting the stocking with an ammonia solution (3%has been found to be satisfactory) so as to promote or accelerate theabsorption or permeation of the rubber particles to the threads; excessammonia may be removed by placing the stockings in a centrifugalmachine-or passing them through a wringer.

The stockings are then ready for immersion in a latex bath. It will beunderstood here that this bath may be any dispersion of rubber, naturalor concentrations of latex are above 5% to 10%. In most instances the;amount of dispersed rubber synthetic, the latex bath being the preferredform and referred to as a matter of convenience.

In every instance where a sheath is formedorated. It will be obviousthat many different. concentrations may be used with different kindsofstockings or knitted articles and under difler ent conditions so as tomake it practically impossible to give any definite concentration of thedispersion; In every case, the dispersed rubber 'bath is of a dilutenature and in the use of a latex bath I have found that the mostdesirable solids concentration will be determined by cut and try method;in most tests I have found that at least a 10% concentration isnecessary to form a substantially continuous and uniform sheath afterthe water evaporates.

Continuing the steps as above set forth, the stockings are next immersedin the dilute latex bath' or subjected to a spray of this same bath,preferably at about room temperature, after .which they may be runthroush a wringer. havrubber sheath. i

ing regulable pressure or a centrifugal machine to remove excess latex,but leave enough latex around each thread to form a thin sheath oirubber after'coagulation. 'The dipping step is of relatively shortduration, usually from fifteen secorids to about two minutes, and afterremoval of the stockings from the" wringer the treated stock- .ings maybe air dried or force dried and the coaxulationof the dispersed rubberparticles together and around the threads is gradual and what might betermed fairly rapid; after this step the stockings may be immersed in ahot water bath for approximately ten minutes at 120 F. tc-obtain apartial vulcanization of the deposited particles of rubber. may takeplace at this point at around 212 F.)

- The stockings are then removed from the hot water bath, machine"dried, preferably by a censtep in electric or steam heat forapproximately thirty minutes at 212 F., after which they are ings maythen be carted or framed in the usual manner so as to stretch and dry tothe proper shape and size. The threads of the sheer stocking's may beoriginally'dyed after the extremely thin sheath of rubber has beenformed around each thread, or the stocking may be redyed, the actualdying step taking place right through the .Another specific method ofcarrying out the invention involves theme of an ammonia bath which maybe a, 3% solution. This ammonia bath may be separated from a dilutelatex bath by wringers and the stockings, after being dipped in theammonia, passed through the 'wringers, very tightly adjusted, and thendipped into the ..dilute latex bath.- The stockings may then be runthrough a. wringer or subjected to a centrifugal action and thenair'dried for' fifteen or twenty minutes to bring about coagulation. Thestockings may then bestretched on a frame and 'dipped into a solution ofsolvent, such as benz'ol, suflicient 'to render the stockings gummy orto slightly melt the latex so as to obtain a strong bond with (Ifdesired, final vulcanization again washed in perfumed soap suds. Thestocka relatively thin solution of latex 'just prior to vulcanizing,after which the stockings may be vulcanized by air drying or suchvulcanization accelerated by heat. In the case of heavy stockings, theymay be dipped in the benzol after vul- -canizing. j

It will'be understood that where the stockingor other knit articles isdipped in a dilute latex solution of correct concentration and atroom-r53 to an hour, will not change this initial condition.

and'the depth of the coating on the removed threads as long as theconcentration and condition of the latex solution remains constant.

It will bethus seen that Ihave produced a knit article the'threads orloops of which lare permanently. tied together to eifectively preventladdering or frunning. Such tying together of the respective loops ismuch more effective than if such loops were really tied together byseparateknots, becaus the fact that the coating which ties the loopstogether at their point of contact also adheres to the threads andthusprevents any possible slipping through or the way alter the normalappearance of the stocking loops. 80.12118 threads of stockings andother knit articles produced bythis process are given such a uniformrubber sheath, either continuous or partially continuous up to andaround the points of contact, which sheath being deposited fromnon-coagulated latex is so thin as to in no or other knit articletreated. In many cases it is impossible to tell the difference in thefeel between an untreated stocking and one treated in accordance withthe present process, andalso practically impossible to tell thediiierence' in appearance with the exception of a slightly differentshade 01 color given to the one stocking by the deposited rubbercoating. There is no difference in feel to the unskilled fingers, but tovery sensitive skilledfingers, the stocking treated according to thepresent process is smoother and is decidedly more sheer in appearance.In all cases wearing qualities are greatly increased; this isparticularly so in the heavier service weight stockings where even athicker sheath of rubber may be deposited around the individual-threads.It will further be seen that stockings treated in accordance with thepresent invention do not ab sorb moisture. The closely woven footportion wears much longer, the whole stocking is spot prooi in thatsmall spots of mud and the like may be easily'rubbed or washedtherefrom, the thin sheath of rubber also makes the article moth proofand prevents shrinkage.

It will be understood that any of the well known aqueous dispersions ofrubber and similar materials may be used ior carrying out the inventionas long as such dispersions or colloids, or whatever name is given them,may be diluted sufliciently to produce when coagulated a relatively thinsheath; either around the entire thread or suiiicient .to tie thethreads together at their points of contact: accordingly, the wordrubber" is used in the claims in a generic sense and contemplates thevarious known dispersions,

mersing the articles fora relatively long time in a bath of latexmaintained .at relatively high coagulating temperatures.

An important feature of this invention is that a thin film of an aqueousdispersion of rubber.

or the like is formed around each discrete thread, either by dipping orspraying, and this coating is in non-coagulated form; after removal ofexcess latex orthe like, such as by pressing through a wringer, thecontinuous thin coating is then coagulated to form a thin substantiallyuniform and continuous sheath oi rubber. Where the latex viscoagulatcdin the bath as in the patentto' Teague No. 1,845,569, and in the patentto Drey fus 1,870,408, the deposit of the coagulated particles of rubberon the threads must be discontinuous and now-uniform, even up to a 10%concentration of latex. It is the teaching of the present invention thatto obtain a thin coating of rubber on'a discrete thread, it is necessaryto originally apply the aqueous dispersion of rubber or the like, as .athin non-coagulated film to the I threads.

What Lclaim is: 1. The process or treating silk textiles of the type sowoven as to be subject to laddering, which comprises coating theindividual threads of each discrete loop with an aqueous dispersion ofrubber in dilute vform and containing only sufiicient rubber solids toadhere to the individual threads as a substantially uniformnon-coagulated coating, the spaces between the threads remaining open,precipitating rubber from such dilute dispersion upon the surface oi.each individual thread with a non-coagulated dilute solution 'of anaqueous dispersiono f rubber containing only'sufiicient rubber solids tomechanically adhere as a substantially uniform coating, removing anyaqueous dispersion from the spaces formed by the threads, evaporatingthecarrying agent and depositing the dispersions of rubber in such a thinuniform coating substantially covering each discrete thread so as to notvisibly change the structural appearance of the'original article,

3. The art of treating textile articles of the type havinginterconnected loops of thread to tie said loops ofthread together attheir points oi contact and for protecting the threads against moisture,spotting and moths, which comprises coating the discrete threads of thearticle with a thin non-coagulated solution cons sting of an aqueousdispersion of rubber containing sufflcient rubber solids to mechanicallyadhere as a substantially uniform coating, mechanically removing any ofsaid solution from the spaces between the threads and all excesssolution and evaporating the carrying agent and depositing thedispersions of rubber in such a thin uniform and substantiallycontinuous coating around each loop of thread andadjacent the point ofcontact with'another loop of thread as to not appreciably change thevisible appearance of the original article, and then vulcanizing thethin layer of rubber to substantially tie the adjacent loops together.

4. The art of treating knit articles to prevent running of the loops andfor protecting the threads against moisture, spotting and moths, whichcomprises coating the individual threads of interconnected loops andadjacent their points of contact, with a dilute nOn-coagulated solutionsuch as an aqueous dispersion of rubber and the like adapted to adhereas a thin film and coritaining not less than 5% of coating solids, withthe spaces between the threads free from coating'material,-evaporatingthe carrying agent and depositing said solids wherebyto form a thinsubstantially continuous non-visible and highly flexible coating for thediscrete threads and adjacent their points of contact, uniting thecoatings or separate but adjacent threads at said points of contact totie the threads together, and stretching the article to its proper shapeand size before curing sets in. 5

5. The process of treating knit articles such. as sheer silk stockingsa'nd the like to prevent runs therein, which comprises immersing thesame in an aqueous dispersion of rubber in dilute him but containing notlea than approximately of rubber solids, removing the treated articlesfrom the bath and mechanically reas sheer silkstockings and the likesubject to 4 ed. articles from the bath, depositing the rubber easyladdering which comprises immersing the same in an aqueous dispersion ofrubber in dilute Iorm containing not less than: approximately 10% ofrubber solids, removing the treat solids on the individual threads ofthe articles particularly at their points of contact, mechanicallyremoving excess treating material therefrom, and then vulcaniz'ing saiddeposited rubber solids to bind adjacent threads together at theirpoints of contact.

7. The process of treating knit articles such as sheer stockings and thelike, which comprises covering the individual threads with an aqueousdispersion of rubber in dilute form, said disperslon containing justsufllcient rubber solids (not less than 5%) as to form a thinnon-coagulated sheath around the individual'threads, the spaces betweenthe threads remaining open, precipitating rubberirom such dilutedispersion by coagulation of the particles together and over thesurfaces of the individual threads insubstantially continuous form, andthen drying.

8. The process of treating knit articles, which comprises wetting thearticles with a solution adapted'to accelerate absorption of an aqueousdispersion of rubber, coating the threads of the so treated articleswith a non-coagulated dilute aqueousdispersion of rubber containing-notless than 5% rubber solids, mechanically removing v excess dispersionfrom the articles, and then drying and vulcanizing the treatedarticles."

9. The process of treating knit articles, which comprises wetting thearticles with a'solution adapted to accelerate absorption of an aqueousdispersion of rubber, coating the threads of the so treated articleswith a dilute non-coagulated aqueous dispersion of rubber, mechanicallyremoving excess. dispersion i'rom the articles, and then immersing thearticles in hot water for a suiiiclent time to partially vulcanize theparticles of latex surrounding each individual thread, drying thearticles and then finally vulcanizing same. i

10. The process for strengthening fibrous associationscomprisingdepositing in situ' thereon and substantially uniformly throughout thesame rubber coagula from a dilute aqueous dispersion of rubber of notless than approximately 10% concentration, the resulting rubber beingdistributed throughout the surface of the-fibrous association in such amanner as to be substantially indiscernlble to the eye and imperceptibleto the touch.

11. A silk stocking having the individual threads secured against thepropagation of "runs" 1 and protected against moisture, spotting andsurrounding the individual threads upto their points of contact,saidrubber being deposited from a. coating of non-coagulated aqueousdispersion of rubber on the threads, the respective sheaths 0! rubberbeing merged together at said points or contact whereby to prevent anysevered thread from running" past said points or contact; substantiallyidentical with the product oi. claim 1.

12. A silk' stocking having the individual threads secured against thepropagation of "runs" by a thin substantially continuous sheath of.flexible material substantially surrounding the individual threads upto their points of contact, said material being deposited from a coatingof non-coagulated solution 01' said material on-the threads, therespective sheaths oi flexible material being merged together at saidpoints of contact whereby to prevent any severed thread from runningsheaths or material around the individual threads being so thin as notto appreciably change the normal appearance ofthe original stocking;substantially identical with the product of claim 4.

13. A knit article formed oI-connected relativelywidelybpen loops and athin elastic coating of rubber deposited from a coating of anoncoagulated aqueous dispersion of rubber for substantially coveringdiscrete adjacent loops of thread at their points of contactsubstantially identical-with the product of claim 2.

'14; A knit article formed of connected rela- I tively wide open loopswithwhich is associated a deposit of an aqueous dispersion oi. rubber,

said deposit on the individual fiber components of the knit articlebeing from an original coating of a non-coagulated .dispersion of rubberpast said points ofcontact,- said while on the individual fibercomponents. such as to form an extremely thin sheath substantiallycovering the fiber components, said thin deposit of rubbervaryingaccording to the size and weight of the fiber components but inany substantially covering. and bonding-together discrete'adiacentthreads at theirpoints of contact substantially identical with theproduct 01' 16.,A knit or similar textile articlecomprisring spacedinterwoven threads-bonded together solely at the contacting-areas ofinterweave thereof-by a thin covering of flexible material selectedtromthe group including dispersions,

emulsions or solutions of finely divided rubber or resin particles, saidcovering of material being so thin and transparent as not. toappreciably change the normal appearance of theorig-i inal article;substantially identical with the prodnot of 'claim' 2,

LLOYD GRQFF corms.

